The present invention relates to an apparatus for determining the profile of a product that is to undergo a subsequent physical process. The subsequent physical process is one in which the product profile is needed to insure proper processing of the product.
In the particular embodiment disclosed herein, the specific subsequent physical process includes slicing the product into individual slices on a slicing machine. Such slicing machines are principally, but not exclusively, used for slicing food products such as cheese, meat and pressed or molded meat products.
Typically such slicing machines include a rotating blade and a product feeder that drives the product forward towards the blade so that successive slices are cut from one face of the product. The distance through which the product is advanced between successive cuts of the blade determines the thickness of the slices. Where the product is of uniform shape and density, it may be sufficient to use a single predetermined slice thickness to give a slice or group of slices of the required weight. Further, it may be sufficient to provide an output scale proximate the output side of the blade to measure the current weight of the slice to product and adjust the thickness of the subsequent slice(s) to make the desired unit weight.
In general, however, variations in the shape and density of the product mean that the weight of a slice of a given thickness varies. A previous approach to dealing with this variation is described and claimed in U.S. Pat. No. 4,428,263, which is hereby incorporated by reference. That patent describes a process in which an automatic slicing machine is programmed to vary the thickness of the slices in accordance with a typical weight distribution for the product.
It has also been proposed to make some determination of the cross-sectional area of the product as it is cut. One such system is purportedly disclosed in U.S. Pat. No. 5,136,906, titled “Slicing Machine”, and assigned to Thurne Engineering Co., Ltd. According to that patent, a slicing machine for cutting slices from a product includes a camera arranged to view a cut face of the product, boundary recognition apparatus arranged to process image signals from the camera to determine a boundary of the cut face, calculating apparatus arranged to calculate a parameter characteristic of the cut face from image data corresponding to regions of the cut face within the boundary, and control signal generating apparatus arranged to generate a control signal to control the operation of the slicer in accordance with the determined parameter.
Although the foregoing system may be suitable for low-throughput slicing machines, it is significantly less suitable for high-speed slicing machines, such as those available from Formax, Inc., of Mokena, Ill., under the brand name S-180.TM.. First, by calculating the product profile at the cut face, a very limited amount of processing time is available to perform the calculations that are necessary to ensure the proper thickness of each slice before the cut face must again be imaged for processing the thickness of the next slice. Second, substantial measurement inaccuracies may result from shadowing effects resulting from the relative positions of the illumination source, cut face, and slicing machine components—a problem not addressed in the '906 patent. Third, further measurement inaccuracies are introduced by the apparent assumption that the profiles at the bottom and a side of the product are linear. Finally, by attempting to measure the product profile at the cut face, substantial inaccuracies may be introduced due to the presence of scrap product. One of the goals of the apparatus described in the '906 patent is to remove the inaccuracies introduced by the scrap product. However, by addressing this problem at the cut face, the apparatus of the '906 must necessarily introduce a further level and higher degree of image processing.
The present inventors have addressed many of the foregoing problems inherent in the product profiling operations of prior art apparatus. To this end, they have developed an accurate and cost-effective product profiling apparatus that is suitable for use, for example, in connection with high-speed product slicing machines.